Embodiments of the present invention relate to electrical batteries formed from multiple cylindrical cells.
A conventional electrical battery may be used to power relatively small, lightweight, portable equipment and may itself consist of a series or parallel connection of cells. The design of particular batteries may conform to standard package dimensions such as the common AAA, AA, C, D, and miniature rectangular 9-volt sizes. In a conventional miniature rectangular 9-volt battery package with snap terminals, tub-shaped cells are typically arranged to occupy the entire volume of the package interior.
The useful life of battery operated equipment is primarily affected by the amp-hour capacity of the battery or the single cycle of a rechargeable battery. Further increase in amp-hour capacity is desirable and cannot be achieved without the present invention.
A battery according to various aspects of the present invention includes a retainer and a circuit. The circuit includes a plurality of cells retained in position by the retainer. The circuit provides a positive and a negative conductor to which all of the cells are coupled. When a dimension of the retainer must meet a predetermined maximum, a number of cells may be dictated by a desired cell chemistry and circuit arrangement (series, parallel, or combination series and parallel). When a bundle of cells of identical diameter is desired, the diameter of each cell of the bundle may be maximized so that the bundle snuggly fits within the retainer dimension.
By constraining all cells of the bundle to be of identical diameter, overall manufacturing costs for the battery may benefit from various economies of scale (e.g., unit costs for materials, subassemblies, and labor operations may decrease).
In an exemplary implementation, the retainer may provide an enclosure having a substantially hexahedral interior cavity and a cap through which a first and a second terminal pass current. A series circuit may include the first terminal, a plurality of cylindrical cells, and the second terminal. The cylindrical cells may be arranged in a bundle having all axes of cylindrical symmetry in parallel. All axes of cylindrical symmetry may pass through a plane that includes the terminals. Or, all axes may be substantially parallel to such a plane. By arranging a bundle of cylindrical cells inside a hexahedral cavity, cylindrical cell geometry may provide better discharge or charge characteristics compared to a plurality of close-packed tub-shaped cells as well as lower cost of manufacture, higher reliability, better seal stability, and more uniform unit-to-unit characteristics.
In another implementation, the battery includes an enclosure that supports at least one battery terminal and a vent formed in the battery terminal. The terminal may include a hollow rivet that provides an aperture. The vent may include a filter over the aperture, for example, a sheet of porous foam. Filtered ambient air may pass into the enclosure and discharged vapor from any cell may pass out of the enclosure.